1. Field Of The Invention
This invention relates to a system for simultaneously displaying the stored content of a waveform memory employing semiconductor storage elements and an instant waveform on the screen of a cathode ray tube of an oscilloscope.
2. Description Of The Prior Art
For storing and displaying an electrical signal waveform, there has heretofore been employed an oscilloscope using a bistable storage tube. This is commonly referred to as a memory scope. This device is very expensive and has a defect in the lifetime of the storage tube. Therefore, such a method has recently been employed in which an electrical signal waveform is stored in a semiconductor memory or the like after being converted to digital data and then read out to be converted again to an analog signal for an input to the Y axis of the cathode ray tube. This device has a feature of starting recording a waveform before occurrence of the phenomenon to be measured. With such a device, however, it is impossible to achieve stable observation of two waveforms with reference to their synchronized trigger points as mentioned below.